A/B Roll Editing
Editing from two source VCRs to a third recording VCR. A switcher or mixer
is used to provide effects such as dissolves.

A/B Roll: The use of
alternating scenes, recorded on separate videotape reels (an A roll and a B
roll), to perform dissolves, wipes or other types of video transitions.

AB Roll Editing - Creating
an edit master tape from two source VTRs on a linear editing system, one
contains the A-roll, and the other the B-roll. Transitions other than cuts,
such as dissolves and wipes, are possible.

A-B roll
Videotape editing arrangement in which scenes on tape are played alternately
on VTRs A and B and recorded on VTR C. Typically, the final output recorded
on VTR C contains some scenes from VTR A and some scenes from VTR B with
transitions (cuts, mixes, wipes etc.) between the scenes.

AB ROLL EDIT - Here we have
the next level of editing, and more equipment to control.
1. two play decks
2. one record deck
3. one edit control - this will set the in-points on all the decks and the
out-point on the appropriate deck.
4. one switcher - this unit will allow you to choose the type of Transition,
used - cut - dissolve - wipe, and so on -
5. the switcher may be a stand-alone unit or a computer such as the Video
Toaster. This unit is controlled by a GPI trigger, which synchronizes the
tape change and the transition.

AB ROLL EDITING can be a very time consuming
process, because of the time necessary to find and cue all of the scenes.
Both decks both must back up, cue and roll at the same time. This process
alone is time consuming and makes the A/B roll editing, slow.

A type of mix where the output at any point in the
picture consists exclusively of whichever input signal had the greater
amplitude. This is in contrast to a normal Mix
which produces a linear sum of the inputs.

A transition between two video signals in which the
signal with the highest instantaneous amplitude is passed.

Known as a NAM, the non-additive mix combines two
pictures by controlling their luminance level relative to each other as
well as a set mix percentage. This popular video switcher effect has been
included to satisfy those die-hard online video editors.